As is known, the development of solution mined cavities requires to have casing shoes in such a position to optimise shape and size.
Due to vibrations, falling rocks or undesirable downhole conditions, the pipes may bend, fracture or collapse. In such cases, optimised development of the reservoir is no longer guaranteed, necessitating the cutting of pipes.
A number of methods for achieving said cutting have been developed and proven. The operation is generally chosen based on price, availability, safety and environmental considerations, including size, depth, surface conditions of the pipes and the cleanliness of the cut.
The main existing methods are:                Explosive charges, chemical or plasma products, which are hazardous to store, transport and work with,        Mechanical blades perform cuts from electric cable or coiled tubing units but have limitations with regard to pipe size,        Abrasive methods used by work-over rigs that perform cuts using a mechanical cutting tool at the end of the pipe string within the casing to be cut.        
All of these methods have their own limitations, advantages and disadvantages, including success rate, operating time while the underground system is on stand-by and the possibility to subsequently run logging instruments.
There follows a brief description of the operation, advantages and disadvantages of the best known cutting methods:
Explosive Methods—Segmented Cutter
Based on detonating a charge with a particular shape and producing a metal flow that penetrates the target. The most widely cutter on electric lines. Suitable for large diameter pipes. Must be centred to achieve a complete cut.
Advantages: reliable, light, quick to mobilise and use.
Disadvantages: the cut is not clean, logging operation cannot be performed safely after the cut, damages to the outer pipe
Explosive Methods—Split Shot
Based on detonating a charge in a vertical configuration with an electric line. Used at the collar level. Produces a vertical cut.
Advantages: reliable, light, quick to mobilise and fast to operate. Can be run through small size pipes, able to cut larger size casings if run through restrictions.
Disadvantages: the cut is not clean, logging operation cannot be performed safely after the cut, damages to outer pipe.
Abrasive—Abrasive Cutter
Based on a rotating tool with nozzles on a coiled tubing in order to cut a pipe with a mixture of water, brine, oil and sand.
Advantages: clean cut, safe running of wireline operations.
Disadvantages: high price, time for mobilisation and deployment, difficult control of the cut, success rate, damages to outer pipe.
Rotating Blades
Based on a rotating blade powered by an electric motor. Maximum diameter of 5½″ (larger sizes in development).
Advantages: clean cut, reliable, no dangerous product handling, logging operation can be performed safely after the cut.
Disadvantages: expensive logging instrument, not available for diameters above 6⅝″.
Chemical Cutter
Based on the use of Bromine trifluoride (BrF3) forced through an oil/steel mixture. The BrF3 reacts with oil and ignite the steel wool. Requires clean pipe, centralizing, anchoring, differential pressure.
Advantages: clean cut, logging operation can be performed safely after the cut.
Disadvantages: BrF3 is dangerous, incomplete cuts happen often, damages to outer pipe.
Radial Cutting Torch
Based on an exothermic reaction. Produces a blast that causes a stream of molten plasma.
Advantages: not explosive, quick to mobilize, fast, no chemical hazards, clean cut, logging operation can be performed safely after the cut, works with stainless chrome, cuts in all liquids and in dry pipes.
Disadvantages: not available for diameters above 8⅝″, expensive, damages to outer pipe.
The U.S. Pat. No. 4,144,936 document describes a down hole milling or grinding system which comprises a hydraulic motor suspended in the hole driven by sea water to rotate an electrical generator and to rotate a cutting tool. The tool comprises radially movable; electrically conductive elements which form the cathodes of an electrochemical machining operation for removing metal and contact elements which form the anodes. The rotation of the cutting tool causes the movement outwardly from the rest position to the contact position of the electrically conductive elements and the contact elements.
In view of all of the above, the objective of the present invention is to offer an alternative method to those already known, based on an electrochemical cutting tool with the advantages of providing a very clean cut, with no dangerous products and able to cut any pipe or casing within a wide range of diameters.
Nevertheless, in reference to the current state of the art, it should be noted that, while many known types of equipment, mechanisms and devices exist for cutting pipes of the type in question, none have the particular technical, structural or constituent characteristics presented by the tool described herein, the distinguishing characteristics of which are described in the final claims accompanying these specifications.